Location estimates

ABSTRACT

A device obtains at least one characteristic of at least one radio signal detected at a mobile device that is located at a particular site and a representation of a radio environment for the site and a definition of at least one specified path section for the site. The at least one path section has been specified by a person in a map presented on a display. The device determines a location estimate for the mobile device based on the at least one characteristic of the at least one radio signal and based on the representation of the radio environment for the site and adjusts the determined location estimate based on the definition of at least one specified path section.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to GB Application No. 1610159.4, filedJun. 10, 2016, the entire contents of which are incorporated herein byreference.

FIELD OF THE DISCLOSURE

The invention relates to the field of positioning and more specificallyto improving location estimates, in particular though not exclusivelylocation estimates that are to be presented on a map, like an indoormap.

BACKGROUND

Satellite signal based positioning technologies, which are mainly usedoutdoors, are usually not suited to deliver a satisfactory performancewhen used for indoor positioning, since satellite signals of globalnavigation satellite systems (GNSS), like the global positioning system(GPS), do not penetrate through walls and roofs strongly enough for anadequate signal reception indoors. Thus, these positioning technologiesare not able to deliver a performance indoors that would enableseamless, equal and accurate navigation experience outdoors and indoors.

Therefore, several dedicated solutions for indoor positioning have beendeveloped and commercially deployed during the past years. Examplescomprise solutions that are based on pseudolites, which are ground basedGPS-like short-range beacons, ultra-sound positioning solutions,Bluetooth low energy (BLE) based positioning solutions, cellular networkbased positioning solutions and wireless local area network (WLAN) basedpositioning solutions.

A WLAN based positioning solution, for instance, may be divided in twostages, a training stage and a positioning stage.

In the training stage, learning data is collected. The data may becollected in the form of fingerprints that are based on measurements bymobile devices. A fingerprint may contain a location estimate andmeasurements taken from a radio interface. The location estimate may befor example GNSS based, sensor-based, or manually inputted. Measurementstaken from the radio interface may comprise, by way of example, measuredradio signal strengths and an identification of WLAN access pointstransmitting the radio signals. The training may be a continuousbackground process, in which mobile devices of a large number ofconsumers are continuously reporting measured data to a server.Consumers may consent to a participation in such a data collection, iftheir device is equipped with the needed functionality. This approach isalso referred to as crowd-sourcing. A crowd-sourcing based trainingstage may enable an exhaustive survey of a site, for instance allfloors, spaces and rooms of a building, in a short time at limitedcosts. Alternatively or in addition, mobile devices may be used forcollecting fingerprints in a systematic manner. Collected fingerprintdata may be uploaded to a database in a server or in the cloud, wherealgorithms may be run to generate radio models of WLAN access pointsand/or radio maps for positioning purposes.

In the positioning stage, a mobile device may estimate its currentlocation based on own measurements taken from the radio interface and onthe data or a subset of data that is available from the training stage.Model data or radio map data that has been generated in the trainingstage may be transferred to mobile devices by a server via the Internetas assistance data for use in position determinations. Alternatively,model data and/or radio map data may be stored in a positioning serverto which the mobile devices may connect to via the Internet forobtaining a position estimate.

A similar approach could be used for a positioning that is based onother types of terrestrial transmitters or on a combination of differenttypes of terrestrial transmitters.

SUMMARY OF SOME EMBODIMENTS OF THE INVENTION

An example embodiment of a method according to the invention comprisesobtaining at least one characteristic of at least one radio signaldetected at a mobile device that is located at a particular site. Themethod moreover comprises obtaining a representation of a radioenvironment for the site and a definition of at least one specified pathsection for the site, the at least one path section having beenspecified by a person in a map presented on a display. The methodmoreover comprises determining a location estimate for the mobile devicebased on the at least one characteristic of the at least one radiosignal and based on the representation of the radio environment for thesite. The method moreover comprises adjusting the determined locationestimate based on the definition of at least one specified path section.The actions may be performed by a single device or in a distributedmanner by two or more devices.

An example embodiment of a first system according to the inventioncomprises means for causing performance of the actions of any presentedembodiment of the example method.

The means of the first system may be implemented in hardware and/orsoftware. They may comprise for instance at least one processor forexecuting computer program code for realizing the required functions, atleast one memory storing the program code, or both. Alternatively, theymay comprise for instance circuitry that is designed to realize therequired functions, for instance implemented in a chipset or a chip,like an integrated circuit.

An example embodiment of a second system according to the inventioncomprises at least one processor and at least one memory includingcomputer program code, the at least one memory and the computer programcode configured to, with the at least one processor, cause at least onedevice at least to perform the actions of any embodiment of thepresented example method.

Any of the described systems may comprise only the indicated componentsor one or more additional components. Any of the described systems maycomprise one or more devices.

Moreover an example embodiment of a non-transitory computer readablestorage medium or a set of non-transitory computer readable storagemedia, in which computer program code is stored, is presented. Thecomputer program code causes at least one device to perform the actionsof any embodiment of the presented example method when executed by atleast one processor.

The computer readable storage medium may be for example a disk or amemory or the like. The set of computer readable storage media may befor example a set of memories. The computer program code may be storedin the at least one computer readable storage medium in the form ofinstructions encoding the at least one computer-readable storage medium.The at least one computer readable storage medium may be intended fortaking part in the operation of at least one device, like an internal orexternal hard disk of a computer, or be intended for distribution of theprogram code, like an optical disc.

It is to be understood that any embodiment of the computer program codeby itself has to be considered an example embodiment of the invention aswell. The computer program code could also be distributed to severalcomputer readable storage media.

In certain embodiments, the presented method is an information providingmethod, and the presented first system is an information providingsystem. In certain embodiments, the means of the presented first systemare processing means.

In certain embodiments, the presented method is a method for improvinglocation estimates. In certain embodiment, any of the presented systemsis a system for improving location estimates.

It is to be understood that any feature presented for a particularexample embodiment may also be used in combination with any otherdescribed example embodiment of any category and any aspect.

Further, it is to be understood that the presentation of the inventionin this section is merely exemplary and non-limiting.

Other features of the present invention will become apparent from thefollowing detailed description considered in conjunction with theaccompanying drawings. It is to be understood, however, that thedrawings are designed solely for purposes of illustration and not as adefinition of the limits of the invention, for which reference should bemade to the appended claims. It should be further understood that thedrawings are not drawn to scale and that they are merely intended toconceptually illustrate the structures and procedures described herein.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is a schematic block diagram of an example embodiment of asystem;

FIG. 2 is a flow chart illustrating an example embodiment of a method;

FIG. 3 is a schematic block diagram of a further example embodiment of asystem;

FIG. 4 is a flow chart illustrating a first example embodiment of amethod in the system of FIG. 3;

FIG. 5 is a diagram illustrating part of the method of the flow chart ofFIG. 4;

FIG. 6 is a flow chart illustrating a second example embodiment of amethod in the system of FIG. 3;

FIG. 7 is a schematic block diagram of an example embodiment of a deviceof the system of FIG. 3;

FIG. 8 is a flow chart illustrating an example embodiment of a firstpart of a method performed by the device of FIG. 7;

FIG. 9 is a diagram illustrating part of the method of the flow chart ofFIG. 8;

FIG. 10 is a flow chart illustrating an example embodiment of a secondpart of a method performed by the device of FIG. 7;

FIG. 11 is a diagram illustrating part of the method of the flow chartof FIG. 10; and

FIG. 12 is a diagram illustrating a variation of the method of the flowcharts of FIGS. 4, 8 and 10.

DETAILED DESCRIPTION OF THE FIGURES

FIG. 1 is a schematic block diagram of an example embodiment of a systemaccording to the invention. System 100 comprises at least one processor101 and, linked to the at least one processor 101, at least one memory102. The at least one memory 102 stores computer program code forimproving location estimates. The computer program code may bedistributed to a plurality of memories 102. The computer program codemay be example computer program code according to the invention, and theat least one memory 102 may be an example computer readable medium or anexample set of computer readable media according to the invention. Theat least one processor 101 is configured to execute computer programcode stored in the at least one memory 102 in order to cause at leastone device to perform desired actions. If two or more processors 101 areconfigured to execute computer program code stored in two or morememories 102 in order to cause two or more devices to perform desiredactions, the two or more devices may be caused to perform the actions ina complementary manner.

System 100 may be a device or comprise at least two interacting devices.System 100 may be for instance a mobile device, like a mobilecommunication device, or a stationary device, like a server, or acombination of a server and a mobile device, or a combination of twomobile devices, or a combination of a mobile device and another userdevice, like a personal computer (PC) or a work station. A mobile deviceis configured to enable operations while the device is moving. Astationary device is configured to be stationary when in operationand/or fixed to a particular location. A stationary device may be groundbased and thus stationary with respect to Earth or only stationarywithin a particular environment, like a ship. System 100 may equally beor comprise at least one module, like a chip, circuitry on a chip or aplug-in board, for at least one device. Optionally, system 100 maycomprise various other components, like a user interface, a datainterface, a further memory, a further processor, etc.

An example operation of system 100 will now be described with referenceto the flow chart of FIG. 2. The operation is an example embodiment of amethod according to the invention. Processor(s) 101 and the program codestored in memory(-ies) 102 cause at least one device to perform theoperation when program code is retrieved from memory(-ies) 102 andexecuted by processor(s) 101. The at least one device that is caused toperform the operation may for instance correspond to system 100,comprise system 100 or be comprised by system 100.

The at least one device obtains at least one characteristic of at leastone radio signal detected at a mobile device that is located at aparticular site. (action 201) The site may be an indoor site, but it mayequally be an outdoor site or comprise outdoor areas. The at least onedevice performing the action may but does not have to correspond to themobile device.

The at least one device furthermore obtains a representation of a radioenvironment for the site and a definition of at least one specified pathsection for the site, the at least one path section having beenspecified by a person in a map presented on a display. (action 202) Arepresentation of a radio environment may be any kind of data thatallows determining characteristics of radio signals that may be expectedto be observed at different geographic locations of a site. Thedefinition of the at least one specified path section may be of any kindthat allows linking the path section directly or indirectly to acorresponding section at the site. If the path section has the form of astraight line, it may be defined for instance by a start point and anend point of the line; if it is a polygon chain, it may be defined forinstance by a start point, one or more intermediate points and an endpoint. Each start, end or intermediate point may be defined by acoordinate value of a geographical location at the site corresponding tothe point in the map. The coordinate values may be for instancelongitude and latitude values, or coordinate values of a coordinatesystem defined specifically for the site. Alternatively, a path sectionmay be defined for instance in terms of adjacent grid points of avirtual grid covering the site. It is to be understood that a specifiedpath section does not have to be limited to a line or a polygon chain.The person having specified the at least one path section willgenerally, though not necessarily, be another person than the user ofthe at least one device or the user of the mobile device. In someembodiments, the definition of the at least one specified path sectionmay be integrated as a part of the representation of the radioenvironment for a site and thus be obtained along with therepresentation of the radio environment.

The at least one device furthermore determines a location estimate forthe mobile device based on the at least one characteristic of the atleast one radio signal and based on the representation of the radioenvironment for the site. (action 203)

The at least one device furthermore adjusts the determined locationestimate based on the definition of at least one specified path section.(action 204)

In open spaces indoors, a pedestrian may generally move freely. In ahall, for example, every path across the hall may be taken. However,when it comes to crossing indoor boundaries, for instance when goingfrom one space to another, there may be a single allowed path via, forinstance, a door. When determining location estimates for a mobiledevice of a user while the user moves between spaces, the locationestimates may indicate a movement from one space to another across awall, in case no special measures are taken. This may result in adverseuser experience, when the user sees this taking place on an indoor mapon which the location estimates are visualized. In practice it hasproven difficult to automate the process of extracting a graph requiredfor movement restriction from an indoor map, for instance a floor plan.Also, it is difficult to detect, in which parts of the indoor space therestricting graph should be used and in which not. To exemplify, amovement restricting graph may be used in a corridor and from there torooms. However, such a graph may rather not be useful in a hall oratrium, because there people can wander freely. Automating suchdifferentiation is notoriously difficult.

Certain embodiments of the invention therefore provide that at first, alocation estimate for a mobile device is determined based on radiosignals received at the mobile device and a representation of a radioenvironment that is available for the site at which the mobile device isknown to be located. Then, the location estimate may be adjusted, ifappropriate. One or more path sections are specified for the site as abasis for such adjustments. The path sections may have been specifiedmanually in a map that is presented on a display, since a person mayintuitively know where it is possible to move around freely and where amovement is not possible due to obstacles or not allowed.

A path section may be for instance a section that is assumed by theperson specifying the path section to have the highest likelihood tocontain a representation of a geographical location that is close to atrue location of a mobile device in the case a location estimate for themobile device is determined to lie in the immediate surrounding of thepath section. Path sections may be defined for any location at whichsome kind of guidance of location estimates is considered to be ofpotential use. It is possible, for example, to specify path sectionspassing through doors, including entrances to and exits from a building,or other narrow passages between spaces. By specifying a path sectionthat passes through a narrow passage, location estimates may be adjustedto approach the defined path section such that they are guided to movethrough the passage, rather than through adjacent walls. It is alsopossible, for example, to specify path sections turning around corridorcorners, since otherwise a presented sequence of location estimates mayoccasionally “cut the corner”. Such a cutting of corners may take placemore often in an environment with a low number of beacons or an unevendistribution of beacons transmitting the radio signals. By specifying apath section that turns around a corner, location estimates may beadjusted to approach the specified path section such that they rather donot cut the corner. It is also possible, for example, to specify pathsections running along long narrow corridors. Such corridors are highlysusceptible for a sequence of location estimates sheering into nearbyrooms etc. By specifying a path section along a narrow corridor, thelocation estimates may be adjusted to follow the corridor more smoothly.

Certain embodiments of the invention may thus have the effect that theyimprove the performance of location estimation for a mobile device atkey locations, for instance when moving from indoors to outdoors or viceversa.

System 100 illustrated in FIG. 1 and the method illustrated in FIG. 2may be implemented and refined in various ways.

In example embodiments, a map of the site is presented on a display andthe adjusted location estimate is indicated in the map. The display maybe the display of the mobile device, for which the location isestimated, or the display of another device. Furthermore, the displaymay be a display of the device determining and adjusting the locationestimate, or a display of another device. If the site is or comprises abuilding, the presented map may be for instance a floor plan.Furthermore, the presented map may be for instance a two-dimensionalfloor plan of the site or a three-dimensional plan of a floor or of abuilding.

Due to the adjustment of the location estimate, the user experience withlocation estimates presented in a map on a display may be improved, asthe presentation of location estimates indicating movements throughwalls or across other obstacles may be reduced significantly by theadjustment of originally determined location estimates.

In example embodiments, adjusting the determined location estimate basedon the definition of at least one specified path section comprisesselecting one of the at least one specified path section that meets atleast one predetermined criterion, and adjusting the determined locationestimate based on the definition of the selected specified path section.This may have the effect that only a specified path section that may berelevant for a current location estimate forms the basis of anadjustment of the location estimate.

In example embodiments, selecting one of the at least one specified pathsection that meets at least one predetermined criterion comprisesselecting a specified path section that is closest to the determinedlocation estimate, or selecting a specified path section with which aninfluence area is associated, in which the determined location estimateis determined to lie. The latter option also provides evidence that thelocation estimate is close to the selected specified path section. Ifthe determined location estimate is assumed to have a certain accuracy,it may also be assumed that only close specified path sections may berelevant for an adjustment.

In example embodiments, the specified path section is only selected incase it meets at least one further predetermined criterion. That is, aclose path section is only considered further, in case it meets someother criterion in addition. This may have the effect that it ispossible to further differentiate between path sections that maypotentially be relevant based on any available information that may besuitable for such a differentiation.

Example embodiments further comprise for instance determining adirection of movement of the mobile device. The at least one furtherpredetermined criterion may then require that the definition of aspecified path section comprises an indication that the path section hasno directionality or a directionality corresponding to the determineddirection of movement. This has the effect that only path sections maybe considered for the adjustment of the location estimate that arecompatible with the direction of movement of the mobile device. Such anindication of directionality may be included in the definition of aspecified path section for instance in case a door is an entrance-onlyor an exit-only door. For instance, in case a door may only be passed inone direction and a path section through this door has been specifiedand associated with an indication of this direction, but the determinedmovement of the device is in the opposite direction, it is unlikely thatthe user of the mobile device is about to pass through this door.

Movement information for a mobile device may be derived for instancefrom a sequence of at least two location estimates. Instead of movementinformation, it is also possible to use heading information of themobile device.

If movement information is not available, the directionality of a pathsection may exploited for taking the location estimate to the rightdirection, when it has been detected that the user is on the pathsection.

It is to be understood that the definition of a specified path sectionmay include other indications that may form the basis for othercriteria, which may be considered alternatively or in addition. Afurther indication may be for example an indication of an existence ofsteps on the specified path section. This may have the effect that adirection of movement including e.g. a change in height of determinedlocation estimates may be taken into account when checking whether anyspecified path section should be considered for adjusting locationestimates. This may have the effect that location estimates can beadjusted to move smoothly according to the steps along the special path.

In general, it has to be noted that a path section may also be specifiedsuch that it comprise a vertical dimension.

It has to be noted that the definition of a path section may comprisefurther information that may not be exploited for the selection of apath section but only after a path section has been selected, e.g. forpresentation to a user. For example, a definition of a path section withassigned direction may be supplemented with information that the pathsection goes from indoor to outdoor, or in general from any firstcertain area to any second certain area. This would enable, forinstance, not only a presentation of location estimates—partlyadjusted—to a user, but in addition or alternatively e.g. an audiooutput providing corresponding information to a user.

In example embodiments, the definition of the at least one specifiedpath section comprises an indication of one of at least two types ofpath sections. Adjusting the determined location estimate based on thedefinition of the selected specified path section may then comprisedetermining and taking account of the type of the selected specifiedpath section. This may have the effect that different structuralsituations may be handled differently. It is to be understood that theaspect of differentiating between two or more types of specified pathsections is also to be considered an invention on its own, irrespectiveof how the path section are specified.

In example embodiments, a type of a path section is one of a restrictingtype or a pulling type or a guiding type (or optionally any furthertype). In case a selected path section is of a restricting type,adjusting a determined location estimate may comprise adjusting thedetermined location estimate to lie within a target area associated withthe selected path section, at least if the determined location estimateis close to the selected path section. In case a selected path sectionis of a pulling type, areas closer to the selected path section may begiven a higher weight than other areas when adjusting a locationestimate, at least if the determined location estimate is close to theselected path section. Depending on the structural situation, thepulling type may cause the location estimate to be gently pulled towardsthe specified path section, while the restricting type may cause asnapping of the location estimate into a sub-space comprising the pathsection. The restricting type may be used for instance for doors orother narrow passages connecting two spaces. The pulling type may beused for instance for long narrow corridors, or at corridor corners,where there is more freedom to the movements of a user. In case aselected path section is of a guiding type, adjusting a determinedlocation estimate is based on an evaluation of a sequence of at leasttwo determined location estimates. This may have the effect that aconfirmation may be obtained that the specified path section hasactually been traversed before a location estimate is adjusted.

It is to be understood that a restricting type, a pulling type and aguiding type may be supported in any combination in certain embodiments.

It is to be understood that one of the supported types of path sectionsmay be a default type. That is, if a definition of a path section isenabled to differentiate between types, but no type is indicated, thepath section may be assumed to be of the default type.

It is to be understood that a differentiation between different types ofpath sections is not essential. If there is no differentiation, thedefinition of a specified path section does not have to include anyindication of the type. The kind of adjustment may then be the same forall path sections.

An adjustment of a location estimate may be realized in many differentways. It may comprise for instance a shift of the determined locationestimate to a new location, and a shifted location estimate may then beused for instance alternatively or in addition to the determinedlocation estimate.

In example embodiments, adjusting a determined location estimatecomprises shifting a location estimate, which lies within an influencearea associated with the selected path section, to the closest point onthe selected path section. In a variation, adjusting a determinedlocation estimate comprises shifting a location estimate, which lieswithin an influence area associated with the selected path section, to aclosest point in a target area associated with the selected pathsection.

Alternatively, adjusting a determined location estimate comprisesshifting the determined location estimate in direction of the selectedpath section, wherein a relative distance by which the determinedlocation estimate is shifted is selected to be the larger the closer thedetermined location estimate is to the selected path section.Optionally, such an adjustment may take place only, in case thedetermined location estimate lies within a predetermined distance to theselected path section.

Further alternatively, adjusting a determined location estimatecomprises, with the determined location estimate being a first locationestimate that is determined based on a representation of a radioenvironment for the entire site, determining a second location estimatebased on a representation of a radio environment for a sub-spacecomprising the selected path section, and choosing the second locationestimate as adjusted location estimate in case the first locationestimate and the second location estimate lie within a predetermineddistance to each other.

Further alternatively, adjusting a determined location estimatecomprises, with the determined location estimate being a first locationestimate that is determined based on a representation of a radioenvironment for the entire site, determining a second location estimatebased on a representation of a radio environment for a sub-spacecomprising the selected path section, and choosing the second locationestimate as adjusted location estimate in case the first locationestimate lies within a predetermined distance to the sub-space.

Further alternatively, adjusting a determined location estimatecomprises, with the determined location estimate being a first locationestimate that is determined based on a representation of a radioenvironment for the entire site, and in case the first location estimatelies within a predetermined influence area, determining a secondlocation estimate based on a representation of a radio environment for asub-space comprising the selected path section, and choosing the secondlocation estimate as adjusted location estimate.

Further alternatively, adjusting a determined location estimatecomprises, with the determined location estimate being a first locationestimate that is determined based on a representation of a radioenvironment for the entire site, determining a distance of the firstlocation estimate to a closest point of the selected path section, andin the case the distance falls short of a predetermined value,determining a second location estimate based on a representation of aradio environment for a sub-space comprising the selected path section,and choosing the second location estimate as adjusted location estimate.

Representations of a radio environment for a sub-spaces comprising arespective path section may be defined and stored in advance and beobtained e.g. along with the representation of a radio environment forthe site. Alternatively, a representation of a radio environment for asub-space comprising the selected path section may be determined whenneeded, for instance based on the obtained representation of a radioenvironment for the site.

For the above four example alternatives, the first location estimate andthe second location estimate are determined for the same point in time.

Further alternatively, adjusting a determined location estimatecomprises, with the determined location estimate being a first locationestimate that is determined based on at least one characteristic of theat least one radio signal detected at the mobile device at a firstinstance of time, determining a second location estimate based on atleast one characteristic of the at least one radio signal detected atthe mobile device at a second instance of time, and supplementing thefirst location estimate and the second location estimate withintermediate location estimates, the intermediate location estimatesbeing determined such that a route from the first location estimate tothe second location estimate via the intermediate location estimatespasses at least one target area associated with the selected pathsection.

Further alternatively, adjusting a determined location estimatecomprises, with the determined location estimate being a first locationestimate that is determined based on at least one characteristic of theat least one radio signal detected at the mobile device at a firstinstance of time, determining a second location estimate based on atleast one characteristic of the at least one radio signal detected atthe mobile device at a second instance of time, and supplementing thefirst location estimate and the second location estimate withintermediate location estimates, in case the first location estimatelies in a first influence area associated with the selected path sectionand the second location estimate lies in a second influence areaassociated with the selected path section or with a further selectedpath section. In this approach, the adjustment may be based on evidencethat the selected path section has actually been traversed, e.g. if thelocation estimates determined for the first and second time instance liein influence areas on different sides of a wall that is connected by adoor through which a selected path section or a combination of selectedpath sections passes. The intermediate location estimates may thenensure that an indicated connection between the first and secondlocation estimate passes via the intermediate location estimates andthus via the door.

A supplementary intermediate location estimate may be considered toconstitute an adjusted location estimate, which may be determined in thesame manner based on an originally determined location estimate aspresented for adjusted location estimates that may replace an originallocation estimate.

If the adjusted location estimates are presented on a display, in thelatter two alternatives, the second location estimate may be presentedonly after the intermediate location estimates have been presented.

A system may support only one of these alternatives of adjusting adetermined location estimate or at least two. It may also supportfurther alternative or additional approaches for adjusting a determinedlocation estimate.

Definitions of areas that are associated with path sections may beobtained as a part of the definition of at least one specified pathsection, for instance based on an input of the person who specified thepath sections, or such areas may be determined based on predefinedrules, e.g. as a rectangles of predetermined width and of a length thatis equal or proportional to the length of the path section. Such areasassociated with a path section may be of different kinds, depending forexample on the type of path section. An influence area may be associatedwith a path section, which indicates a desired possible influence of thepath section on all location estimates within this influence area.Another area may be associated with a path section, which indicates atarget area for adjusted location estimates. Such a target area, ifdefined, may be contained for instance in an influence area. Theinfluence area as well as the target area may at least partially containthe specified path section with which they are associated. In thesimplest case, any area may be defined by a stripe of certain widthcentered along the specified path, i.e. an area may be a rectanglecentered along the path and having certain width. Alternatively, theoutlines of an area may be defined, which may also support more complexshapes than rectangles. In example embodiments, it may also be possiblethat two or more areas of the same kind are associated with a singlepath section, in particular with different parts of the path section.

In example embodiments, the obtained at least one characteristic of aradio signal comprises an indication of a received signal strength ofthe radio signal. Using received signal strength related values as acharacteristic of radio signals may have the effect that such values maybe determined for transmissions of any kind of beacon. It may furtherhave the effect that they may be measured at a receiving end withoutestablishing any connection with the transmitting end. An indication ofa received signal strength of a radio signal may be for instance areceived signal strength indication (RSSI) or a physical Rx level in dBmwith a reference value of 1 mW, etc. Another kind of indication of areceived signal strength of a radio signal may be for instance anindication of a path loss of a radio signal at a particular location.Other possible characteristics may comprise a timing advance (TA) valueor a round-trip time value.

A representation of a radio environment may be for instance a grid basedradio map indicating for each grid point characteristics of radiosignals that may be expected to be observed from identified beacons at ageographic location corresponding to the grid point. Using grid basedradio maps as representations of the radio environment may have theeffect that the data may reflect details of the real radio environmentparticularly well.

Alternatively, a representation of a radio environment may comprise forinstance parameter values of a set of parametric radio models for radiosignals transmitted by beacons at the localization site. Using parametervalues of parametric radio models may have the effect that the requiredamount of data for defining the radio environment of a site may beparticularly small. The radio models may model any characteristic ofradio signals transmitted by a beacon at various locations. An exampleof a parametric radio model is a path loss model for radio signalstransmitted by a beacon. In this case, the parameters may comprise anidentification of the beacon, a location of the beacon, a path lossexponent and an indication of a transmission power used by the beacon.

The beacons transmitting the radio signals that are reflected in therepresentation of the radio environment of a site may comprise any kindof terrestrial transmitter, in particular, though not exclusively, anykind of non-cellular terrestrial transmitter. In example embodiments,the beacons comprise a wireless local area network access point and/or aBluetooth beacon and/or a Bluetooth beacon enabling Bluetooth low energymode and/or a Bluetooth low energy beacon. It is to be understood thatin some embodiments, characteristics of radio signals from differenttypes of beacons on the site may be considered.

WLAN access points and Bluetooth beacons are already installed in manybuildings. Furthermore, WLAN and Bluetooth technologies are supported bymany mobile user devices by default, like by most smartphones, tablets,laptops and feature phones. Using characteristics of signals transmittedby WLAN access points, Bluetooth beacons and/or BLE beacons may thushave the effect that the supported positioning may be based in someembodiments on an existing infrastructure in buildings and/or onexisting capabilities in many mobile devices. As a result, the approachmay be globally scalable and have low maintenance and deployment costs.The deployment of new infrastructure, including for example beacons andtags, is possible but not necessary. In addition, the end-userexperience may be acceptable with these technologies, since a horizontalpositioning accuracy of 2-3 meters as well as close to 100% reliabilityin floor detection may be achieved. The beacons may be stand-alonedevices or be integrated into or attached to some other device. The useof Bluetooth low energy may enable a positioning with limited energyconsumption at all involved devices. A Bluetooth beacon that is employedfor the invention may be any kind of Bluetooth beacon complying with anypresent or future standard.

It is to be understood, however, that other types of beacons thanvariations of WLAN access points or Bluetooth beacons may be consideredas well, for instance tags or other devices that are configured totransmit ultra-wideband (UWB) signals or ultra-sound signals or anywireless signals that might emerge in the future.

If the considered beacons comprise alternatively or in addition acellular transmitter, the beacons may comprise for instance a basestation of a Global System for Mobile Communications (GSM) network, of aCDMA2000 network, of a Universal Mobile Telecommunications System (UMTS)network, of a long term evolution (LTE) network, or of any other currentor future kind of cellular network.

FIG. 3 is a schematic block diagram of an example embodiment of a systemsupporting an improvement of a user experience with location estimatespresented on a map.

The system comprises at least one mobile survey device 300, a server310, at least one mobile user device 320 that may need to know its ownposition, and a plurality of beacons 330.

Mobile survey device 300 may be for instance a regular mobile terminal,like a smartphone or general purpose tablet PC, or a dedicated surveydevice.

Mobile survey device 300 comprises a processor 301 that is linked to afirst memory 302, to a second memory 304, and to an interface 305 forcellular communication, to at least one interface 306 for receivingsignals from beacons 330, a GNSS receiver 308 and a touchscreen 309.

Processor 301 is configured to execute computer program code, includingcomputer program code stored in memory 302, in order to cause mobilesurvey device 300 to perform desired actions. It is to be understoodthat processor 301 may comprise or have access to a working memory forthis purpose, for example in the form of a random access memory (notshown).

Memory 302 stores computer program code for assembling fingerprints,computer program code for presenting a map on touchscreen 309 and forenabling a specification of path sections in the map, and computerprogram code for causing a transmission of data to server 310. Inaddition, memory 302 may store computer program code configured torealize other functions. Memory 302 may also store for instance anoperating system for mobile survey device 300. In addition, memory 302may store any kind of data.

Processor 301 and memory 302 may optionally belong to a module 303, likea chip or an integrated circuit or any other kind of processingcircuitry, which may comprise in addition various other components, forinstance a further processor or a further memory.

Memory 304 is configured to store data, including for examplefingerprint data, definitions of path sections and floor plans asexample map data. In addition, memory 304 may also store any kind ofdata.

Interface 305 is configured to enable communications with other devicesvia a cellular communication network 340 and further, for example, viathe Internet 350. It may be or belong to a cellular engine.

The at least one interface 306 is configured to detect signals from oneor more kinds of beacons 330, for instance BLE beacons and/or WLANaccess points, and optionally to enable a communication via one or morekinds of beacons 330.

GNSS receiver 308 may comprise any kind of global navigation satellitesignal receiver, for example a GPS receiver and/or a GLONASS receiverand/or a GALILEO receiver. It may be configured to receive correspondingsatellite signals and to determine the current position of mobile surveydevice 300 based on the signals, possibly using assistance data. Suchassistance data may be received for instance from a server via theInternet 350 and cellular communication network 340.

Touchscreen 309, as an example display, enables a visual presentation ofdata to a user. In addition, it enables the input of a user via thedisplay. It is to be understood that in addition to touchscreen 309,mobile survey device 300 may comprise various other user interfacecomponents, like buttons, keys, a microphone, a loudspeaker, etc.

Mobile survey device 300 may comprise further components not shown.

Server 310 may be for instance a dedicated location server or a generalpurpose server. It may be provided for supporting a positioning ofmobile devices at a particular localization site or for supporting apositioning at a plurality of localization sites. Server 310 comprises aprocessor 311 that is linked to a first memory 312, to a second memory314, and to an interface 315.

Processor 311 is configured to execute computer program code, includingcomputer program code stored in memory 312, in order to cause server 310to perform desired actions. It is to be understood that processor 311may comprise or have access to a working memory for this purpose, forexample in the form of a random access memory (not shown).

Memory 312 stores computer program code for generating radio maps fromreceived fingerprints, computer program code for receiving and storingdata on path sections specified by a user in a map presented on adisplay and computer program code for supporting a positioning of mobiledevices by providing assistance data and/or by determining and providinglocation estimates. All of this computer program code may belong forinstance to a radio map generation application. In addition, memory 312may store computer program code configured to realize various otherfunctions. Memory 312 may also store for instance an operating systemfor server 310. In addition, memory 312 may store any kind of data.

Processor 311 and memory 312 may optionally belong to a module 313, likea plug-in board or a chip or an integrated circuit or any other kind ofprocessing circuitry, which may comprise in addition various othercomponents, for instance a further processor or a further memory.

Memory 314 is configured to store data, including for example floorplans for at least one site, received fingerprint data, grid based radiomap data and associated definitions of path sections. In addition,memory 314 may also store any kind of data. It is to be understood thatmemory 314 could also be external to server 310.

Interface 315 is configured to enable a communication with otherdevices, for instance via the Internet 350.

It is to be understood that server 310 may comprise various othercomponents, like a user interface.

Component 303 with component 313 or mobile survey device 300 with server300 may also be an example embodiment of a system of the invention.

Mobile user device 320 may be for instance a regular mobile terminal,like a smartphone or general purpose tablet PC, or it may be forinstance an Internet of Things (IoT) device, like a smart watch or asmart band, etc. It is configured to perform measurements on signalstransmitted by at least one type of beacons 330, and to access theInternet 350, for instance via a cellular communication network 340 or aWLAN, in order to communicate with server 310. It is further configuredto compute its own position or to obtain a computed location estimatefrom server 310 upon request.

The beacons 330 may be for instance WLAN access points and/or BLEbeacons. They are distributed at a localization site, by way of examplein a large building like a shopping mall, such that at least one beaconmay be observed at essentially each location of the localization site atwhich a positioning of mobile user devices 320 is to be supported.

Cellular communication network 340 may be of any type; it may be forinstance, though not exclusively, a GPRS, UMTS or LTE network.

FIG. 4 is a flow chart illustrating first example operations of mobilesurvey device 300 and server 310 in the system of FIG. 3. Processor 301and some of the program code stored in memory 302 may cause mobilesurvey device 300 to perform the actions presented with double lineswhen the program code is retrieved from memory 302 and executed byprocessor 301. Processor 311 and some of the program code stored inmemory 312 may cause server 310 to perform the actions presented withsingle lines when the program code is retrieved from memory 312 andexecuted by processor 311. The purpose of the operations of FIG. 4 is togenerate enhanced positioning assistance data for a localization site.Mobile survey device 300 and sever 310 may perform corresponding actionsseparately for each of a plurality of localization sites. It is to beunderstood that, in particular for different sites, server 310 may alsointeract with different mobile survey devices 300 to this end. It isfurther to be understood that if server 310 is provided for a singlesite, mobile survey device 300 may also interact in a similar mannerwith different servers 310 for different sites.

A user of mobile survey device 300 has activated an application forcollecting data as a basis for positioning assistance data for aparticular localization site, for instance a particular building.

Mobile survey device 300 presents a floor plan on touchscreen 309 toassist the user in the collection of data. (action 401) The requireddata may be retrieved from memory 304. The data for floor plans for allfloors of the particular building or for several buildings may have beenreceived for example from server 310 and stored in memory 304. Theparticular building may be identified by a user input, and the floorplan that is presented may be based on a user input with respect to thefloor on which the user is currently located. Alternatively, buildingand/or floor may be determined automatically based on position andaltitude determined by GNSS receiver 308 of mobile survey device 300.

While mobile survey device 300 moves around at the localization site, itscans for radio signals from beacons 330 in its environment at regularintervals. Whenever device 300 detects at least one radio signal duringa scan, it measures the received signal strength (RSS) of each radiosignal and extracts an identifier of the transmitting beacon, e.g. amedium access control (MAC) address of a transmitting BLE beacon or WLANaccess point, from the radio signal. The measured radio signal strengthvalues may then be considered to be characteristics of the observedradio signals. (action 402)

In addition, mobile survey device 300 obtains an indication of itscurrent position at each location at which measurements are performedduring a scan. To this end, GNSS receiver 308 may capture satellitesignals and estimate the position of mobile survey device 300 at thesame regular intervals in which scans for radio signals are performed,for example once per second. (action 403) Since satellite signals may bedifficult to receive within buildings, such a positioning may be anassisted GNSS (AGNSS) based positioning using available assistance data.The assistance data may be provided for example by some GNSS assistanceserver via cellular communication network 340. The indicated positionobtained by mobile survey device 300 may have a horizontal component,for instance a longitude value and a latitude value, or easting andnorthing values. In addition, it may comprise an indication of the flooron which the user is located. The indication of the floor may beobtained for instance from a general input by the user when reaching anew floor. Alternatively, the position estimated by GNSS receiver 308may include an altitude component, and the altitude may be mapped to arespective floor based on a reference altitude of the ground floor andsome general or building specific information on the height of floors.It is to be understood that alternatively or in addition, other meansmay be used for determining the locations of measurements. For example,the user of device 300 may be required to enter information on arespective measurement location, for instance based on a grid coveringthe floor plan presented on touchscreen 309.

The RSS values and the associated beacon IDs obtained during a scan aswell as the indication of the location of measurement obtainedessentially at the same point in time are assembled as a fingerprint andstored in memory 304 until the survey of the localization site has beencompleted for the time being. (action 404)

In parallel, the user of mobile survey device 300 considers whether anyof the areas he/she passes may benefit from a restriction/guidance ofpossible location estimates. If so, the user draws a line on touchscreen309 into the presented floor plan to specify a corresponding pathsection at the site, along which a movement can be expected to takeplace in a certain area. For instance, when passing from one space toanother, the passage can be expected to take place through a providedconnection, like a door. Each path section may be specified for instanceby means of a drawn straight line or a drawn sequence of straight lines.Mobile survey device 300 may only enable the input of straight lines.Alternatively, mobile survey device 300 may convert a drawn line into astraight line or a sequence of straight lines for facilitating thedefinition of a specified path section.

For illustration, FIG. 5 presents a floor plan of a house with twoentrances. Bold lines 501 indicate lines or a sequence of lines drawn bya user into the floor plan on touchscreen 309. Two single bold lines runthrough the entrance doors and specify corresponding preferred pathsections at the site. Another preferred path section specified by adrawn single line (not shown) could run for instance along a long narrowcorridor. A sequence of lines may be drawn by the user for instance incase the preferred path section turns around a corner. This isillustrated in FIG. 5 by the L-shaped sequence of two bold lines.Another preferred path section that may be specified by a sequence oflines (not shown) could be for example the way up- or down a staircase.

Mobile survey device 300 detects a user input drawing lines ontouchscreen 309 to specify path sections. (action 405)

In addition, mobile survey device 300 may provide the option to the userto further specify the specified path sections. For instance, once aline specifying a path section has been drawn, double tapping onto theline may result in a presentation of available, selectable options,including a deletion of the specified path section.

For instance, a user may be enabled to further specify a path section byindicating a directionality. This may be of interest for instance incase a door is an entrance-only or exit-only door. Mobile survey device300 may detect a corresponding user input. (action 406)

For instance, a user may be enabled to further specify a path section byspecifying a type of the path section. Two or more types may be defined,for instance a restricting type, a pulling type and a guiding type. Arestricting type may require a location estimate for instance to snap toa close surrounding of the specified path section. A pulling type maygently pull the estimate towards the specified path section. This typemay also be referred to as gravitating type. A guiding type may takeaccount of a sequence of location estimates for deciding on anadjustment. A default type may be assigned to each specified pathsection, which may be changed by a user if desired. Mobile survey device300 may detect a corresponding user input. (action 407)

In the example of FIG. 5, a restricting type (“Restricting”) may beassigned for instance to the two path sections specified by linespassing through a respective door depicted in the floor plan, as thedoors enable only small variations in movement from one space to theother. A pulling type (“Pulling”) may be assigned for instance to thepath section specified by the L-shaped line in the floor plan, and guidethrough a wide corridor.

Furthermore, a user may be enabled to further specify a path section forinstance by defining one or more areas associated with each specifiedpath section. (action 408) For example, an influence area may bedetermined automatically for each specified path section usingpredefined rules. If another size or shape is considered moreappropriate by the user considering the situation on site, he may adjustthe automatically determined influence area. It may be ensured thatinfluence areas are generally not overlapping and that a user definitionof overlapping influence areas is not accepted. For example, a targetarea may be determined automatically for each specified path section ofrestricting type using predefined rules, such that the target area lieswithin the influence area and encompasses the path section. If anothersize or shape is considered more appropriate by the user considering thesituation on site, he may adjust the automatically determined targetarea. Alternatively, it may be provided that the user defines theinfluence area and/or the target area in any case and that no automaticdetermination is provided. An area defined by a user may be rectangularor of any other shape.

Mobile survey device 300 stores definitions of the specified pathsections in memory 304. (action 409) For determining a definition of aspecified path section, mobile survey device 300 may, for example, map aline drawn in the floor plan on touchscreen 309 to a correspondinggeographic section at the localization site and define this geographicsection by coordinates, like longitude and latitude values or eastingand northing coordinates. An indication of the coordinates for each pathsection may then be supplemented with the selected type anddirectionality, if any, to obtain the final definition of a specifiedpath section.

The fingerprints of various scans stored in memory 304 and thedefinitions of path sections stored in memory 304 are transmitted toserver 310. (action 410) This transmission may take place for instancewhen the survey of the building or of a floor of the building has beencompleted.

Server 310 receives the fingerprints and associated definitions of pathsections from mobile survey device 300 for the localization site.(action 411) Optionally, it may receive further fingerprints for thesame localization site from a plurality of other mobile devices.

Server 310 uses the fingerprints collected at the localization site forgenerating a grid based radio map as an example representation of theradio environment of the site. (action 412)

A virtual grid is defined to cover the localization site such that eachgrid point corresponds to a geographical location at the site. If thelocalization site comprises several floors, a separate grid may bedefined for each floor, or a single three dimensional grid may bedefined with one dimension for the different floors.

A radio map may be generated by mapping the RSS value(s) and theassociated beacon ID(s) of each fingerprint to the grid point thatcorresponds to a geographical location that is closest to themeasurement location indicated in the fingerprint. If there are severalRSS values for the same beacon that would be mapped to the same gridpoint, some kind of average value may be used, for instance thearithmetic mean or the median value. For grid points to which no RSSvalues could be mapped due to missing fingerprints from thecorresponding areas at the localization site, RSS values may begenerated by interpolating surrounding RSS values if possible, and byextrapolating neighboring RSS values otherwise. Alternatively, theoriginal or mapped RSS values could be used for estimating for eachbeacon parameter values for a path loss model, and the pass loss modelcould then be used for mapping all or missing RSS values to grid pointsof the grid.

Server 310 stores the radio map data for the site and the associateddefinitions of path sections in memory 314. The definitions of pathsections may be stored as separate information, but in some embodiments,they could also be stored as an integral part of the radio map data. Tothis end, the path sections and related information could also be mappedto corresponding grid points of the grid. If stored separately, thedefinition of the path sections as such may be stored for instance invector form. This may have the effect that the definition can be moreaccurate and yet be compact. The radio map data may be further processedbefore storage, for example compressed. The stored data is provided aspositioning assistance data enabling determination and adjustment oflocation estimates. (action 413) It may be provided either fortransmission to a requesting device or for positioning computations thatare to be performed by serer 310. The requesting device may be a mobiledevice, of which the location is to be estimated, or another device.

An example use of the positioning assistance data will be described inmore detail further below with reference to FIGS. 7 to 11.

In a variation of the operations illustrated in FIG. 4, the pathsections could also be specified by a user in advance before starting tocollect the fingerprints. In another variation, the path sections couldalso be specified by a user any time after the fingerprints have beencollected and used for generating a radio map. It may be noted that inboth cases, the user device does not necessarily have be configured toassemble fingerprints; it does not even have to be a mobile device.Using a mobile device may have the effect, though, that a user isenabled to evaluate the map in view of the actual structural situationat the localization site, which may help in defining path sections.

FIG. 6 is a flow chart illustrating example alternative operations ofmobile survey device 300 and server 310 in the system of FIG. 3, inwhich path sections are specified later on. Processor 301 and some ofthe program code stored in memory 302 may cause mobile survey device 300to perform the actions presented with double lines when the program codeis retrieved from memory 302 and executed by processor 301. Processor311 and some of the program code stored in memory 312 may cause server310 to perform the actions presented with single lines when the programcode is retrieved from memory 312 and executed by processor 311. Thepurpose of the operations of FIG. 6 is equally to generate enhancedpositioning assistance data for a localization site.

In a training stage, server 310 obtains and stores fingerprints for arespective localization site from a plurality of mobile survey devices.These devices may or may not include survey device 300. Each fingerprintmay comprise again an indication of a measurement location together withbeacon IDs and associated RSS values. The beacons 330 may comprise againWLAN access points and/or BLE beacons. (action 601)

Server 310 generates a radio map based on the stored fingerprint datafor a respective localization site, for instance as described withreference to action 412 of FIG. 4. (action 602) The radio map data maybe stored in memory 314.

In a positioning stage, server 310 may then receive requests forpositioning assistance from mobile devices 320 that have to know theirown position. A request may be a request for positioning assistance datafor a particular localization site. This enables the mobile device 320to determine its own position any time while located at the localizationsite and without the need for further communication with server 310.Alternatively, a request may be a request for a location estimate. Inthis case, the request may include in addition the result of radiomeasurements at the current location of mobile device 320. This resultof radio measurements includes at least one RSS value and an associatedbeacon ID. This approach limits the required storage space and theprocessing load at mobile device 320.

When receiving a request for positioning assistance data, server 310retrieves radio map data stored for the localization site from memory314 and transfers it to the requesting mobile device 320. When receivinga request for a location estimate, server 310 retrieves radio map datastored for the localization site from memory 314, estimates the locationof mobile device 320 based on received measurement data and the radiomap data, and transfers the location estimate to mobile device 320.(action 603)

At some point in time, the performance of the positioning at aparticular localization site may be checked.

To this end, a user of mobile survey device 300 enters the localizationsite. Thereupon, mobile survey device 300 presents a map of the site,for instance in the form of a floor plan of the floor on which the useris currently located, on touchscreen 309. (action 611) Optionally, thesite and/or the floor are identified to this end based on a user input.Alternatively, relevant site and/or floor may be inferred based on aposition computed by GNSS receiver 308.

Mobile survey device 300 is then used as one of the mobile devices whichrequest and receive positioning assistance data in the form of radio mapdata from server 310, as described with reference to action 603. Likeother mobile devices, which need to know their own position, mobilesurvey device 300 scans the environment for radio signals while movingaround, and determines RSS values of detected radio signals and the IDsof the beacons that transmitted the radio signals. Mobile survey device300 estimates its locations based on the RSS values and the obtainedradio map data and indicates the location estimates to the user in themap that is presented via touchscreen 309. (action 612)

While the user moves around at the localization site, he/she may monitorwhether the sequence of location estimates are shown to move throughwalls or to cut corners. If so, the user may activate a path selectionapplication, to be able to improve the performance for other users.

Mobile survey device 300 activates in this case a path selectionapplication, in order to enable the user to specify preferred pathsections at the localization site. (action 613)

Mobile survey device 300 detects a user input drawing lines on thetouchscreen 309 for specifying path sections at corresponding locationsat the localization site. (action 614)

Mobile survey device 300 may also detect additional user input furtherspecifying one or more of the specified path sections, for instance byselecting a type of a path section and/or by indicating a directionalityof the path section and/or by defining at least one area associated witha path section. (action 615)

When the user has completed the definitions of path sections for aparticular floor of the site, he/she may continue with action 611 forthe next floor.

Mobile survey device 300 transmits definitions of all path sectionsspecified for all floors of the site, including possibly indicateddirection and type, to server 310. (action 616)

Server 310 receives and stores the definitions of the specified pathsections for the site in association with the stored radio map data forthe site in memory 314. From there on, server 310 may provide thedefinitions of the path sections for a site along with radio map datafor the site in action 603 (either for transmission or for internalcomputations), in order to enable an improved determination of locationestimates. (action 620)

FIG. 7 is a schematic block diagram of an example embodiment of a mobiledevice 320 in the system of FIG. 3. Mobile device enables adetermination of location estimates that may be suited to result in animproved user experience when the location estimates are presented in amap on a display.

Mobile device 320 comprises a processor 321 that is linked to a firstmemory 322, to a second memory 324, and to an interface 325 for cellularcommunication, to an interface 326 for receiving signals from beacons330, and to a user interface including a display 329.

Processor 321 is configured to execute computer program code, includingcomputer program code stored in memory 322, in order to cause mobiledevice 320 to perform desired actions. It is to be understood thatprocessor 321 may comprise or have access to a working memory for thispurpose, for example in the form of a random access memory (not shown).

Memory 322 stores computer program code for requesting and obtainingpositioning assistance data from server 310, computer program code fordetermining a location estimate, computer program code for adjusting thelocation estimates based on path section definitions included in thepositioning assistance data, and computer program code for presentingthe adjusted location estimates in a map on display 329. Some of theprogram code in memory 322 may be similar to some of the program code inmemory 102. In addition, memory 322 may store computer program codeconfigured to realize other functions. Memory 322 may also store forinstance an operating system for mobile survey device 320. In addition,memory 322 may store any kind of data.

Processor 321 and memory 322 may optionally belong to a module 323, likea chip or an integrated circuit or any other kind of processingcircuitry, which may comprise in addition various other components, forinstance a further processor or a further memory.

Memory 324 is configured to store data, including for example data offloor plans for one or more sites, radio map data for one or more sites,and definitions of path sections for one or more sites. In addition,memory 324 may also store any kind of data.

Interface 325 is configured to enable a communication with other devicesvia a cellular communication network 340 and further, for example, viathe Internet 350. It may be or belong to a cellular engine.

Interface 326 is configured to receive signals from one or more kinds ofbeacons 330, for instance BLE beacons and/or WLAN access points.

It is to be understood that in addition to display 329, the userinterface of mobile device 320 may comprise other input and/or outputmeans, like buttons, keys, a microphone, a loudspeaker, etc.

Mobile device 320 may comprise further components not shown.

FIGS. 8 and 10, in combination, represent a flow chart illustratingexample operations of mobile device 320 in the system of FIG. 3.Processor 321 and some of the program code stored in memory 322 maycause mobile device 320 to perform the actions when the program code isretrieved from memory 322 and executed by processor 321. The purpose ofthe operations of FIGS. 8 and 10 is to determine and present enhancedlocation estimates at a localization site.

When some application of mobile device 320 needs to know the position ofmobile device 320 at a particular localization site, mobile device 320may request and receive positioning assistance data for the site fromserver 310 and store the data in memory 324. (action 801) Thepositioning assistance data may be provided by server 310 for example inthe scope of action 413 of FIG. 4 or action 620 of FIG. 6. Thepositioning assistance data includes radio map data. The radio map dataindicates RSS values of signals from identified beacons that areexpected to be observed at each geographical location of the site, whichcorresponds to a grid point of a virtual grid covering the site. Thepositioning assistance data includes in addition definitions of pathsections. A definition of a path section is based on an input of aperson specifying the path section in a map that was presented on adisplay of a mobile survey device 300 or some other device, for exampleas described with reference to FIG. 4 or FIG. 6. The definition of apath section includes an indication of the location of the path sectionat the site, and optionally an indication of an influence areaassociated with the path section, and indication of a target areaassociated with the path section, an indication of a type of the pathsection and/or an indication of a directionality of the path section.The positioning assistance data received by mobile device 320 may alsoinclude data of floor plans for the site. The positioning assistancedata may be stored by mobile device 320 in memory 324.

In addition, mobile device 320 regularly scans for radio signals whilemoving around. It measures RSS values of detected radio signals anddetects the beacon IDs of the beacons 330 transmitting the detectedradio signals at a respective position. (action 802)

Mobile device 320 may regularly estimate its location based on this dataand the received radio map data for the localization site. For each setof RSS values and associated beacon IDs determined at a particular pointin time, a grid point is determined that provides the best match withrespect to mapped RSS values and associated beacon IDs in the radio mapdata. The best match may be determined for instance as the match thatresults in the minimum total difference (determined e.g. as the sum ofabsolute values or as Euclidian distance) between the RSS valuesmeasured for the beacons and the RRS values for these beacons mapped tothe grid point of the grid of the radio map. (action 803) In case morethan one location estimate is determined while mobile device 320 movesalong, also a direction of movement may be determined based onsubsequent location estimates.

The determined location estimate may include an indication of the flooron which the user of mobile device 320 is currently located. This may beachieved by matching detected RSS values with RSS values mapped to gridpoints of grids for each floor. A corresponding floor plan may bepresented on display 329 by the application of mobile device 320 whichrequires the location of mobile device 320.

In case an influence area has been associated with each specified pathsection, mobile device 320 may select a path section, with which aninfluence area is associated that contains the location estimate, ifany, If a direction of movement of mobile device 320 is determined inaction 803, the path section may only be select in this case, if it haseither no directionality assigned or a directionality that essentiallycorresponds to the determined direction of movement of mobile device320. In case no influence area has been associated with each specifiedpath section, mobile device 320 may select instead the closest specifiedpath section to a respective location estimate based on the receiveddefinitions of path sections and the location estimate. In case adirection of movement of mobile device 320 is determined in action 803,mobile device 320 may select in this case more specifically the closestpath section that has either no directionality assigned or adirectionality that essentially corresponds to the determined directionof movement of mobile device 320. For the selected path section, mobiledevice 320 may determine in addition the assigned type, which may berestricting or pulling. (action 804) In addition, or as an alternativeto the restricting type, also a guiding type assigned to a selected pathsection may be supported.

In some cases, no suitable path section may be determined. In this case,the location estimate may be considered to constitute the final locationestimate, and the operation may jump to action 816.

The operation for the case that the type is determined to be“restricting” will be described further below with reference to FIG. 10.This operation may also be the basis for the case that the type isdetermined to be “guiding”; this variation will be described furtherbelow with reference to FIG. 12.

If the type is determined to be “pulling”, mobile device 320 determinesa distance between the location estimate and the closest point on thepath section. (action 811)

If the distance exceeds a predetermined value (action 812), the locationestimate is accepted as the final location estimate (action 813).Actions 812 and 813 may have the effect of saving processing load fororiginal location estimates that are far from any specified path sectionanyhow. In some embodiments, these actions may also be omitted.

FIG. 9 is a diagram of an example floor plan, which corresponds to thefloor plan of FIG. 5 and in which path sections have been specified bymeans of drawn lines 501. Two triangles 521, 522 represent possiblelocation estimates. A triangle 521 with bold lines may represent forinstance a location estimate, for which the closest specified pathsection is represented by the L-shaped lines 511. This path section isof the pulling type. In this example, the distance of the locationestimate (represented by triangle 521) to the closest point of thespecified path section (represented by lines 511) determined in action811 may be determined in action 812 to exceed the predetermined value,so that the location estimate is accepted in action 813 as the finallocation estimate.

The location estimate is presented in the floor plan on display 329.(action 816)

If the distance does not exceed a predetermined value (action 812), thelocation estimate is adjusted.

In the example of FIG. 9, a filled triangle 522 may represent forinstance a location estimate, for which the closest path section isrepresented by the L-shaped lines 511 again. As indicated before, thispath section of the pulling type. The distance of the location estimate(represented by triangle 522) to the closest point of the path section(represented by lines 511) determined in action 811 may be determined inaction 812 not to exceed the predetermined value, so that the locationestimate is adjusted.

For adjusting a location estimate, at first a percentage of thedetermined distance may be computed that is the higher the lower thedetermined distance. Thus, areas closer to the path section are weightedhigher than areas farther away from the path section. (action 814)

Then, the location estimate is adjusted by shifting it in direction ofthe closest point of the path section by the determined percentage ofthe determined distance. The location estimate is thus pulled towardsthe path section. (action 815) The adjusted location estimate may bemuch closer to the path section than the original location estimate.

The adjusted location estimate is presented in the floor plan on display329. (action 816)

The flow chart of FIG. 10 presents further operations for the case it isdetermined in action 804 that the type of the closest path section withmatching directionality to a location estimate is of restricting type.

FIG. 11 is a diagram of an example floor plan, which corresponds againto the floor plan of FIG. 5 and in which path sections have beenspecified by means of drawn lines 501. The entire area for which radiomap data is available is indicated by a rectangle 531 with bold dashedlines. Two diamonds—one with white filling 541 and one with hashedfilling 542—represent possible location estimates. The selected pathsection for each of these location estimates is the path sectionrepresented by line 512. This path section is a path section of therestricting type.

Mobile device 320 determines an area at least partially surrounding theselected path section represented by line 512 as a sub-space. (action821) This sub-space may correspond to a target area defined in action408 of FIG. 4 and obtained in action 801, or it may be computed based onpredefined rules based on the selected path section.

Such an area is represented in FIG. 11 for the selected path section.The area may be limited for example by a rectangle—represented with bolddotted lines 523—that has a length corresponding to the length of thepath section and a widths that provides a predetermined distance to thepath section on either side.

Mobile device 320 defines radio map data for the sub-space around theselected path section. Alternatively, separate radio map data may bereceived from server 310 for each path section of restricting type alongwith the definitions of the path sections. The radio map data for thesub-space assigns RSS values and associated beacon IDs to grid points ofa virtual grid covering the sub-space. This may be achieved in variousways. For instance, simply the RSS values may be used that are assignedto the same grid points in the grid for the entire space. Alternatively,the RSS values that are mapped to the grid points of the virtual gridcovering the sub-space may be determined based only on thosefingerprints that have been received at server 310 for the area of thesub-space. (action 822)

Mobile device 320 already computed a first location estimate based onthe radio map data for the complete localization site in action 803.Now, mobile device 320 computes in addition a second location estimatebased on the radio map data for the determined sub-section. (action 823)

The second location estimate may then be presented as adjusted locationestimate in the map on display 329. (action 824)

In FIG. 11, diamond 541 represents a possible first location estimatethat may have been determined in action 804 to lie outside of theinfluence area associated with any specified path section 501. Such alocation estimate may be considered a final location estimate that isnot to be adjusted.

In FIG. 11, diamond 542 represents another possible first locationestimate that is determined in action 804 to lie within an influencearea associated with path section 512. This may also be interpreted suchthat the first location estimate represented in FIG. 11 by diamond 542lies within a predetermined distance to path section 512 or to targetarea 532.

In FIG. 11, an example second location estimate, computed in action 823based on radio map data for the determined sub-section 532, isrepresented by a filled black diamond 543.

The first location estimate represented in FIG. 11 by diamond 542 isadjusted by being replaced by the newly computed second locationestimate represented in FIG. 11 by diamond 543 for the presentation inaction 824.

FIG. 12 is a diagram illustrating two different variations of theoperations presented so far. FIG. 12 depicts parts of the walls 550 fromthe floor plan of FIG. 5, including the door on the left hand side.

In a first variation, a user of survey device 300 specifies again a pathsection of restricting type passing through the door, for instance inline with actions 405 through 407 of FIG. 4. The path section isrepresented in FIG. 12 with a bold line again. However, in a variationof action 408 of FIG. 4, instead of a single target area, the user ofsurvey device 300 defines two adjacent target areas, represented bydotted lines 552 a and dashed lines 552 b, for the path section. Targetarea 552 a encompasses a portion of the path section represented by afirst part 551 a of the bold line on the left side of the door, andtarget area 552 b encompasses a portion of the path section representedby a second part 551 b of the bold line on the right side of the door.Similarly, instead of a single influence area, the user of survey device300 defines two adjacent influence areas, represented by dotted lines553 a and dashed lines 553 b, for the path section. Influence area 553 acontains target area 552 a and influence area 553 b contains target area552 b. As can be seen by way of example with area 553 b, the areas donot have to be rectangular. In the present case, influence areas 553 aand 553 b have been designed to cover walls close to the door onopposite sides. Alternatively or as a basis, all of the areas could alsobe defined automatically based on the user definition of path section551 a, 551 b.

Now, whenever a location estimate, which may be determined by mobiledevice 320 similarly as in action 803 of FIG. 8, lies within influencearea 553 a, it is adjusted to lie in target area 552 a. In the same way,whenever a location estimate, determined by mobile device 320 similarlyas in action 803 of FIG. 8, lies within influence area 553 b, it isadjusted to lie in target area 552 b. In both cases, the adjustment maybe achieved for example using the same approach as presented for asingle path section with reference to FIG. 10. The alternative approachusing two influence and target areas for a single path section mayensure that whenever estimated locations move in the neighborhood of thedoor, this neighborhood represented by the union of influence areas 553a and 553 b, e.g. from inside (area 553 b) to outside (area 553 a), theadjusted location estimates will not be shown to cross the walls whenpresented in a map on a display, since they only can move from area 552b to area 552 a and vice versa.

It is to be understood that similarly, two or more influence areas maybe defined for different parts of a single path section of the pullingtype.

It is further to be understood that alternatively and equivalently, twoor more separate path sections could be defined by the user of surveydevice 300 in the first place for any passage. In this case, theoperation may be the same as described with reference to FIGS. 4, 6, 8and 10.

FIG. 12 furthermore serves for illustrating the use of a path section ofa guiding type.

At the site, mobile device 320 is not able to move from an arearepresented in FIG. 12 by area 553 a to an area represented in FIG. 12by area 553 b or 552 b without first going through an area representedin FIG. 12 by area 552 a, since otherwise walls represented in FIG. 12by walls 550 are in the way.

This may be reflected in an example embodiment by an adjustment oflocation estimates that is based on a sequence of at least two locationestimates. For example, if a first location estimate is in the area 553a, and consecutive location estimate is in the area 553 b, then twointermediate location estimates, one in area 552 a and one in area 552b, may be added so that the location estimate that is presented movesfrom area 553 a to area 552 a and then to area 552 b and finally to area553 b, which may guarantee that walls are shown to be not crossed. Inthis case, the adjustment of a location estimate may thus comprise anadding of a location estimate.

The guiding type path section can be considered as a special case of arestricting type path section, which is indicated in action 824 of FIG.10. A location estimate in a respective influence area can be adjustedto lie in a respective target area, for example similarly as describedwith reference to FIG. 10, to obtain a respective intermediate locationestimate. The main difference may be seen in that a location estimate isadjusted to lie within the target area only when there is an indicationderived from the sequence of location estimates that mobile terminal 320has gone through a specified path section, e.g. in the case of specifiedpath section 551 a, 551 b, when two consecutive location estimates aredetermined to lie inside area 553 a and area 553 b respectively.

It is to be understood that the presented example systems, apparatusesand operations may be further varied in many ways. The systems andapparatuses may be varied for instance by modifying, adding or omittingcomponents. The operations may be varied for instance by modifyingactions, by omitting actions and/or by adding actions. In addition, theorder of actions may be modified.

For example, in an alternative embodiment, the beacons may include forexample other transmitters than BLE beacons or WLAN access points, forexample regular Bluetooth transmitters or ultra-sound transmitters, etc.

For example, in an alternative embodiment, the location of measurementmay be determined by mobile survey devices by other means than userinput or GNSS based positioning, for instance using a WLAN basedpositioning.

For example, in an alternative embodiment, a separate grid may bedefined for each detected beacon of a site, instead of using a grid, inwhich RSS values of several beacons may be mapped to a grid point, asdescribed with reference to action 412.

For example, in an alternative embodiment, a location estimate may alsobe determined by calculating likelihood values by matching the RSSvalues of at least one beacon with the expected RSS values for the atleast one beacon mapped to grid points of the radio map. Once thelikelihood for different locations has been calculated, the location ofa mobile device may be estimated, for example, as the location for whichthe likelihood achieves the maximum value.

For example, in an alternative embodiment, a set of radio models, forexample path loss models, may be determined in action 412 of FIG. 4 oraction 602 of FIG. 6 as a representation of a radio environment insteadof a radio map. In case a representation of a radio environmentcomprises parameter values of parametric radio models for each detectedbeacon, a location may be estimated by defining circles around beaconpositions defined by the parameter values, the radius of each circlebeing computed using the radio model for the respective beacon and thereceived signal strength value measured for the respective beacon. Thelocation may then be estimated to correspond to an intersection point ofall circles.

For example, in an alternative embodiment, a stationary device mayperform actions 611 to 616 of FIG. 6 instead of mobile survey device300. Such a device does not have to comprise interface 305, interface306 or GNSS receiver 308. Instead, it may have a wired connection to theInternet 350 in order to be able communication with server 300.

For example, in an alternative embodiment, actions 803-815 and actions821-823 of FIGS. 8 and 10 could also be performed by server 310. In thiscase, mobile device 320 only assembles measured RSS values of detectedbeacon signals and the beacon IDs of the beacons 330 transmitting thedetected beacon signals as a radio sample and transmits the radio samplein a message to server 300 along with a positioning request. The finallocation estimate may then be transmitted by server 310 to mobile device320, which presents the location estimate in a map on display 329.

Summarized, certain embodiments of the invention may provide forreference paths of location estimates at key locations. This may improvethe perceived end-user experience at transitions between spaces.

Any presented connection in the described embodiments is to beunderstood in a way that the involved components are operationallycoupled. Thus, the connections can be direct or indirect with any numberor combination of intervening elements, and there may be merely afunctional relationship between the components.

Further, as used in this text, the term ‘circuitry’ refers to any of thefollowing:

(a) hardware-only circuit implementations (such as implementations inonly analog and/or digital circuitry)

(b) combinations of circuits and software (and/or firmware), such as:(i) to a combination of processor(s) or (ii) to portions ofprocessor(s)/software (including digital signal processor(s)), software,and memory(ies) that work together to cause an apparatus, such as amobile phone, to perform various functions) and(c) to circuits, such as a microprocessor(s) or a portion of amicroprocessor(s), that require software or firmware for operation, evenif the software or firmware is not physically present.

This definition of ‘circuitry’ applies to all uses of this term in thistext, including in any claims. As a further example, as used in thistext, the term ‘circuitry’ also covers an implementation of merely aprocessor (or multiple processors) or portion of a processor and its (ortheir) accompanying software and/or firmware. The term ‘circuitry’ alsocovers, for example, a baseband integrated circuit or applicationsprocessor integrated circuit for a mobile phone.

Any of the processors mentioned in this text could be a processor of anysuitable type. Any processor may comprise but is not limited to one ormore microprocessors, one or more processor(s) with accompanying digitalsignal processor(s), one or more processor(s) without accompanyingdigital signal processor(s), one or more special-purpose computer chips,one or more field-programmable gate arrays (FPGAS), one or morecontrollers, one or more application-specific integrated circuits(ASICS), or one or more computer(s). The relevant structure/hardware hasbeen programmed in such a way to carry out the described function.

Any of the memories mentioned in this text could be implemented as asingle memory or as a combination of a plurality of distinct memories,and may comprise for example a read-only memory (ROM), a random accessmemory (RAM), a flash memory or a hard disc drive memory etc.

A bus may be provided for connecting processor(s) and memories.

Moreover, any of the actions described or illustrated herein may beimplemented using executable instructions in a general-purpose orspecial-purpose processor and stored on a computer-readable storagemedium (e.g., disk, memory, or the like) to be executed by such aprocessor. References to ‘computer-readable storage medium’ should beunderstood to encompass specialized circuits such as FPGAs, ASICs,signal processing devices, and other devices.

In example embodiments, any non-transitory computer readable mediummentioned in this text could also be a removable/portable storage or apart of a removable/portable storage instead of an integrated storage.Example embodiments of such a removable storage comprise a magnetic discstorage, of an optical disc storage, a semiconductor memory circuitdevice storage and of a Micro-SD semiconductor memory card storage.

The functions illustrated by processor(s) 101 in combination withmemory(-ies) 102, or processor 321 in combination with memory 322, orcomponent 323 can also be viewed as means for obtaining at least onecharacteristic of at least one radio signal detected at a mobile devicethat is located at a particular site; means for obtaining arepresentation of a radio environment for the site and a definition ofat least one specified path section for the site, the at least one pathsection having been specified by a person in a map presented on adisplay; means for determining a location estimate for the mobile devicebased on the at least one characteristic of the at least one radiosignal and based on the representation of the radio environment for thesite; and means for adjusting the determined location estimate based onthe definition of at least one specified path section.

The program codes in memory 102 or memory 322 can also be viewed ascomprising such means in the form of functional modules.

FIGS. 2, 4, 6, 8 and 10 may also be understood to represent examplefunctional blocks of computer program code improving a user experiencewith location estimates.

It will be understood that all presented embodiments are only examples,and that any feature presented for a particular example embodiment maybe used with any aspect of the invention on its own or in combinationwith any feature presented for the same or another particular exampleembodiment and/or in combination with any other feature not mentioned.It will further be understood that any feature presented for an exampleembodiment in a particular category may also be used in a correspondingmanner in an example embodiment of any other category.

What is claimed is:
 1. A method performed by at least one device, themethod comprising: obtaining at least one characteristic of at least oneradio signal detected at a mobile device that is located at a particularsite, wherein the particular site comprises a plurality of path sectionsincluding at least one path section having a restricting path type, atleast one path section having a pulling path type, and at least one pathsection having a guiding path type; obtaining a representation of aradio environment for the site and a definition of at least threespecified path sections of the plurality of path sections for the site,the at least three path sections having been specified by a person in amap presented on a display, wherein the definition of each of the atleast three specified path sections comprises an indication of one ofthe three types of path sections for the respective specified pathsection; determining a first location estimate for the mobile devicebased on a first characteristic of a first radio signal and based on therepresentation of the radio environment for the site; determining asecond location estimate for the mobile device based on a secondcharacteristic of a second radio signal and based on the representationof the radio environment for the site; determining a third locationestimate for the mobile device based on a third characteristic of athird radio signal and based on the representation of the radioenvironment for the site; and adjusting the determined first locationestimate, the determined second location estimate, and the determinedthird location estimate based on the definition of at least onespecified path section for each determined location estimate, whereinadjusting the respective determined location estimate based on thedefinition of at least one specified path section for each determinedlocation estimate comprises: selecting a first specified path sectionthat is closest to the determined first location estimate or isassociated with an influence area in which the determined first locationestimate is determined to lie, wherein the first specified path sectionhas a restricting type; adjusting the determined first location estimateto lie within a target area associated with the first specified pathsection; selecting a second specified path section that is closest tothe determined second location estimate or is associated with aninfluence area in which the determined second location estimate isdetermined to lie, wherein the second specified path section has apulling type; adjusting the determined second location estimate morestrongly in proportion to proximity of the second specified pathsection; selecting a third specified path section that is closest to thedetermined third location estimate or is associated with an influencearea in which the determined third location estimate is determined tolie, wherein the third specified path section has a guiding type;adjusting the determined third location estimate based on an evaluationof a sequence of at least two determined location estimates.
 2. Themethod according to claim 1, further comprising presenting a map of thesite on a display and indicating the adjusted determined first location,adjusted determined second location, or adjusted determined thirdlocation estimate in the map.
 3. The method according to claim 1,further comprising determining a direction of movement of the mobiledevice based on the first characteristic of the first radio signal;wherein selecting the first specified path section requires thedefinition of the first specified path section comprising an indicationthat the first specified path section has no directionality or adirectionality corresponding to the determined direction of movement. 4.The method according to claim 1, wherein adjusting the determined firstlocation estimate comprises one of: shifting the determined firstlocation estimate, which lies within an influence area associated withthe first specified path section to a closest point on the firstspecified path section; or shifting a location estimate, which lieswithin an influence area associated with the first specified pathsection, to a closest point in a target area associated with the firstspecified path section; or shifting the determined first locationestimate in direction of the first specified path section, wherein arelative distance by which the determined first location estimate isshifted is selected to be the larger the closer the determined firstlocation estimate is to the selected path section; or with the firstlocation estimate that is determined based on a representation of aradio environment for the entire site, determining a fourth locationestimate based on a representation of a radio environment for asub-space comprising the first specified path section, and choosing thefourth location estimate as adjusted location estimate in case the firstlocation estimate and the fourth location estimate lie within apredetermined distance to each other; or with the first locationestimate that is determined based on a representation of a radioenvironment for the entire site, determining a fourth location estimatebased on a representation of a radio environment for a sub-spacecomprising the first specified path section, and choosing the fourthlocation estimate as adjusted location estimate in case the firstlocation estimate lies within a predetermined distance to the sub-space;or with the first location estimate that is determined based on arepresentation of a radio environment for the entire site, and in casethe first location estimate lies within a predetermined influence area,determining a fourth location estimate based on a representation of aradio environment for a sub-space comprising the first specified pathsection, and choosing the fourth location estimate as adjusted locationestimate; or with the first location estimate that is determined basedon a representation of a radio environment for the entire site,determining a distance of the first location estimate to a closest pointof the first specified path section, and in the case the distance fallsshort of a predetermined value, determining a fourth location estimatebased on a representation of a radio environment for a sub-spacecomprising the selected path section, and choosing the fourth locationestimate as adjusted location estimate; or with the first locationestimate that is determined based on at least one characteristic of theat least one radio signal detected at the mobile device at a firstinstance of time and a fourth location estimate based on at least onecharacteristic of the at least one radio signal detected at the mobiledevice at a second instance of time, and supplementing the firstlocation estimate and the fourth location estimate with intermediatelocation estimates, the intermediate location estimates being determinedsuch that a route from the first location estimate to the fourthlocation estimate via the intermediate location estimates passes atleast one target area associated with the first specified path section;or with the first location estimate that is determined based on at leastone characteristic of the at least one radio signal detected at themobile device at a first instance of time, determining a fourth locationestimate based on at least one characteristic of the at least one radiosignal detected at the mobile device at a second instance of time, andsupplementing the first location estimate and the fourth locationestimate with intermediate location estimates, in case the firstlocation estimate lies in a first influence area associated with thefirst specified path section and the fourth location estimate lies in asecond influence area associated with the first specified path sectionor with a further selected path section.
 5. A system comprising at leastone processor and at least one memory, wherein the at least one memoryincludes computer program code, the at least one memory and the computerprogram code configured to, with the at least one processor, cause atleast one device at least to: obtain at least one characteristic of atleast one radio signal detected at a mobile device that is located at aparticular site, wherein the particular site comprises a plurality ofpath sections including at least one path section having a restrictingpath type, at least one path section having a pulling path type, and atleast one path section having a guiding path type; obtain arepresentation of a radio environment for the site and a definition ofat least three specified path sections of the plurality of path sectionsfor the site, the at least three path section having been specified by aperson in a map presented on a display, wherein the definition of eachof the at least three specified path sections comprises an indication ofone of the three types of path sections for the respective specifiedpath section; determine a first location estimate for the mobile devicebased on a first characteristic of a first radio signal and based on therepresentation of the radio environment for the site; determining asecond location estimate for the mobile device based on a secondcharacteristic of a second radio signal and based on the representationof the radio environment for the site; determining a third locationestimate for the mobile device based on a third characteristic of athird radio signal and based on the representation of the radioenvironment for the site; and adjust the determined first locationestimate, the determined second location estimate, and the determinedthird location estimate based on the definition of at least onespecified path section for each determined location estimate, whereincausing the at least one device to adjust the respective determinedlocation estimate based on the definition of at least one specified pathsection for each determined location estimate comprises causing the atleast one device to: select a first specified path section that isclosest to the determined first location estimate or is associated withan influence area in which the determined first location estimate isdetermined to lie, wherein the first specified path section has arestricting type; adjust the determined first location estimate to liewithin a target area associated with the first specified path section;select a second specified path section that is closest to the determinedsecond location estimate or is associated with an influence area inwhich the determined second location estimate is determined to lie,wherein the second specified path section has a pulling type; adjust thedetermined second location estimate more strongly in proportion toproximity of the second specified path section; select a third specifiedpath section that is closest to the determined third location estimateor is associated with an influence area in which the determined thirdlocation estimate is determined to lie, wherein the third specified pathsection has a guiding type; adjust the determined third locationestimate based on an evaluation of a sequence of at least two determinedlocation estimates.
 6. The system according to claim 5, wherein the atleast one memory and the computer program code are further configuredto, with the at least one processor, cause at least one device topresent a map of the site on a display and to indicate the adjusteddetermined first location, adjusted determined second location, oradjusted determined third location estimate in the map.
 7. The systemaccording to claim 5, wherein the at least one memory and the computerprogram code are further configured to, with the at least one processor,cause at least one device to determine a direction of movement of themobile device based on the first characteristic of the first radiosignal, wherein selecting the first specified path section requires thedefinition of the first specified path section comprising an indicationthat the first specified path section has no directionality or adirectionality corresponding to the determined direction of movement. 8.The system according to claim 5, wherein adjusting the determined firstlocation estimate comprises one of: shifting the determined firstlocation estimate, which lies within an influence area associated withthe first specified path section to a closest point on the firstspecified path section; or shifting a location estimate, which lieswithin an influence area associated with the first specified pathsection, to a closest point in a target area associated with the firstspecified path section; or shifting the determined first locationestimate in direction of the first specified path section, wherein arelative distance by which the determined first location estimate isshifted is selected to be the larger the closer the determined firstlocation estimate is to the selected path section; or with the firstlocation estimate that is determined based on a representation of aradio environment for the entire site, determining a fourth locationestimate based on a representation of a radio environment for asub-space comprising the first specified path section, and choosing thefourth location estimate as adjusted location estimate in case the firstlocation estimate and the fourth location estimate lie within apredetermined distance to each other; or with the first locationestimate that is determined based on a representation of a radioenvironment for the entire site, determining a fourth location estimatebased on a representation of a radio environment for a sub-spacecomprising the first specified path section, and choosing the fourthlocation estimate as adjusted location estimate in case the firstlocation estimate lies within a predetermined distance to the sub-space;or with the first location estimate that is determined based on arepresentation of a radio environment for the entire site, and in casethe first location estimate lies within a predetermined influence area,determining a fourth location estimate based on a representation of aradio environment for a sub-space comprising the first specified pathsection, and choosing the fourth location estimate as adjusted locationestimate; or with the first location estimate that is determined basedon a representation of a radio environment for the entire site,determining a distance of the first location estimate to a closest pointof the first specified path section, and in the case the distance fallsshort of a predetermined value, determining a fourth location estimatebased on a representation of a radio environment for a sub-spacecomprising the selected path section, and choosing the fourth locationestimate as adjusted location estimate; or with the first locationestimate that is determined based on at least one characteristic of theat least one radio signal detected at the mobile device at a firstinstance of time and a fourth location estimate based on at least onecharacteristic of the at least one radio signal detected at the mobiledevice at a second instance of time, and supplementing the firstlocation estimate and the fourth location estimate with intermediatelocation estimates, the intermediate location estimates being determinedsuch that a route from the first location estimate to the fourthlocation estimate via the intermediate location estimates passes atleast one target area associated with the first specified path section;or with the first location estimate that is determined based on at leastone characteristic of the at least one radio signal detected at themobile device at a first instance of time, determining a fourth locationestimate based on at least one characteristic of the at least one radiosignal detected at the mobile device at a second instance of time, andsupplementing the first location estimate and the fourth locationestimate with intermediate location estimates, in case the firstlocation estimate lies in a first influence area associated with thefirst specified path section and the fourth location estimate lies in asecond influence area associated with the first specified path sectionor with a further selected path section.
 9. A non-transitory computerreadable storage medium or a set of non-transitory computer readablestorage media, in which computer program code is stored, the computerprogram code causing at least one device to perform the following whenexecuted by at least one processor: obtain at least one characteristicof at least one radio signal detected at a mobile device that is locatedat a particular site, wherein the particular site comprises a pluralityof path sections including at least one path section having arestricting path type, at least one path section having a pulling pathtype, and at least one path section having a guiding path type; obtain arepresentation of a radio environment for the site and a definition ofat least three specified path sections of the plurality of path sectionsfor the site, the at least three path section having been specified by aperson in a map presented on a display, wherein the definition of eachof the at least three specified path sections comprises an indication ofone of the three types of path sections for the respective specifiedpath section; determine a first location estimate for the mobile devicebased on a first characteristic of a first radio signal and based on therepresentation of the radio environment for the site; determining asecond location estimate for the mobile device based on a secondcharacteristic of a second radio signal and based on the representationof the radio environment for the site; determining a third locationestimate for the mobile device based on a third characteristic of athird radio signal and based on the representation of the radioenvironment for the site; and adjust the determined first locationestimate, the determined second location estimate, and the determinedthird location estimate based on the definition of at least onespecified path section for each determined location estimate, whereincausing the at least one device to adjust the respective determinedlocation estimate based on the definition of at least one specified pathsection for each determined location estimate comprises causing the atleast one device to: select a first specified path section that isclosest to the determined first location estimate or is associated withan influence area in which the determined first location estimate isdetermined to lie, wherein the first specified path section has arestricting type; adjust the determined first location estimate to liewithin a target area associated with the first specified path section;select a second specified path section that is closest to the determinedsecond location estimate or is associated with an influence area inwhich the determined second location estimate is determined to lie,wherein the second specified path section has a pulling type; adjust thedetermined second location estimate more strongly in proportion toproximity of the second specified path section; select a third specifiedpath section that is closest to the determined third location estimateor is associated with an influence area in which the determined thirdlocation estimate is determined to lie, wherein the third specified pathsection has a guiding type; adjust the determined third locationestimate based on an evaluation of a sequence of at least two determinedlocation estimates.